Re: [Scikit-learn-general] PCA nipals and SparsePCA

2014-05-31 Thread bthirion
Dear Luca, If I understand correctly, your approach is deflationary PCA that uses the l1 prox to enforce sparsity. I am not sure how this compares to the lars-based implementation of the scikit (the non-convexity of the problem makes it hard to compare algorithms). Moreover, I have run you

Re: [Scikit-learn-general] [GSOC] blogging progress

2014-05-31 Thread Manoj Kumar
Hello everyone, I have blogged about my progress this week, http://manojbits.wordpress.com/2014/05/31/gsoc-2nd-week-roadblocks-and-progress/ On Fri, May 23, 2014 at 6:00 PM, Olivier Grisel wrote: > Thanks Manoj! > > BTW, if you use the Rackspace Cloud account for your next benchmarking > sessi

Re: [Scikit-learn-general] A question about the SVM module

2014-05-31 Thread Mathieu Blondel
On Sat, May 31, 2014 at 9:22 PM, Mathieu Blondel wrote: > K_test = pairwise_kernels(X_train, X_test, metric="sigmoid") > This line should read K_test = pairwise_kernels(X_test, X_train, metric="sigmoid") Mathieu -- T

Re: [Scikit-learn-general] A question about the SVM module

2014-05-31 Thread Mathieu Blondel
You can always train a LinearSVC directly on the kernel matrix. This won't be exactly the same as a kernel SVC [*] but it doesn't make any PSD assumption. K_train = pairwise_kernels(X_train, metric="sigmoid") clf = LinearSVC() clf.fit(K_train) K_test = pairwise_kernels(X_train, X_test, metric="si

Re: [Scikit-learn-general] A question about the SVM module

2014-05-31 Thread Gael Varoquaux
On Sat, May 31, 2014 at 06:15:44PM +0800, Benjamin Li wrote: > In [1], Lin suggest an implementation of SVM for non psd kernels. > So my question is does scikit learn handle this case. No. Gaƫl -- Time is money. Stop was

Re: [Scikit-learn-general] A question about the SVM module

2014-05-31 Thread Benjamin Li
Dear Nelle, Thanks for your reply. I do understand that the majority of kernels are psd. Yet I am currently dealing with non psd kernel such as sigmoid kernel in [1] and optimal assignment kernel in [2, 3]. In [1], Lin suggest an implementation of SVM for non psd kernels. So my question is does sc

Re: [Scikit-learn-general] Manual categories/separate classifiers

2014-05-31 Thread Tim Head
Hi Gilles, On 23 May 2014 15:06, Gilles Louppe wrote: > Hi Tim, > > In principles, what you describe exactly corresponds to the decision tree > algorithm. You partition the input space into smaller subspaces, on which > you recursively build sub-decision trees. > Exactly. What I was wondering wa